From 6bfe0f0418df97b00fd9ee3fffa02b5b40a293d6 Mon Sep 17 00:00:00 2001
From: Matthew Chen <matthew@signal.org>
Date: Fri, 1 Feb 2019 10:22:33 -0500
Subject: [PATCH] Ensure 'link new device' view is portrait.

---
 .../categories/UIViewController+OWS.m           | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/SignalMessaging/categories/UIViewController+OWS.m b/SignalMessaging/categories/UIViewController+OWS.m
index eb923067f..04c1ba1d8 100644
--- a/SignalMessaging/categories/UIViewController+OWS.m
+++ b/SignalMessaging/categories/UIViewController+OWS.m
@@ -15,11 +15,19 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (UIViewController *)findFrontmostViewController:(BOOL)ignoringAlerts
 {
+    NSMutableArray<UIViewController *> *visitedViewControllers = [NSMutableArray new];
+
     UIViewController *viewController = self;
     while (YES) {
+        [visitedViewControllers addObject:viewController];
+
         UIViewController *_Nullable nextViewController = viewController.presentedViewController;
         if (nextViewController) {
             if (!ignoringAlerts || ![nextViewController isKindOfClass:[UIAlertController class]]) {
+                if ([visitedViewControllers containsObject:nextViewController]) {
+                    // Cycle detected.
+                    return viewController;
+                }
                 viewController = nextViewController;
                 continue;
             }
@@ -27,8 +35,13 @@ NS_ASSUME_NONNULL_BEGIN
 
         if ([viewController isKindOfClass:[UINavigationController class]]) {
             UINavigationController *navigationController = (UINavigationController *)viewController;
-            if (navigationController.topViewController) {
-                viewController = navigationController.topViewController;
+            nextViewController = navigationController.topViewController;
+            if (nextViewController) {
+                if ([visitedViewControllers containsObject:nextViewController]) {
+                    // Cycle detected.
+                    return viewController;
+                }
+                viewController = nextViewController;
             } else {
                 break;
             }